[popnbrown]

Second Jacob's idea, try using EasyC.

Other than that what are you using right now to program the robot?

I'm using Kevin Watson's code.

Thing about the Pressure Switch, is that whenever the Pressure gets ablve a certain point it sends a signal out to the RC (there should be a connection between the Pressure Switch and the RC). What you do is you check and see if this signal is on (usually a 1) or off (a 0). When its on you will want to turn off the compressor.

The pressure switch is a digital input and the compressor is a relay output.

Figure out which port number for your compressor and pressure switch.
Then using Kevin Watson's code, where XX stands for your port number

relayXX_fwd = !rc_dig_inXX;
relayXX_rev = 0;

Hope that helps!
Sravan